ALAMEDA -- An initial U.S. Coast Guard investigation into a July collision between a freight ship and the Richmond-San Rafael Bridge has found that a small sailboat played a role in the collision.

Around 4:30 p.m. on July 11, the 590-foot freight ship Pacific Highway, which was carrying automobiles, hit the fendering system of the bridges north support tower while en route to Benicia.

According to the Coast Guard, the impact did not cause any injuries, but did cause some damage to the bridge's fendering system. There was also some damage to the port side of the freight ship.

Investigators found that the Della Brown, a 34-foot sailboat, was in the vicinity of the ship at the time of the collision.

The Coast Guard's Marine Safety Office for the San Francisco Bay is recommending a civil penalty against the operator of the Della Brown for impeding the passage of the freight ship.

According to the Coast Guard, the sailboat operator violated Rule 9 of the Inland Rules of the Road. The maximum penalty for violating this rule is $6,500, according to the Coast Guard.

The office is forwarding the results of its investigation to Coast Guard Headquarters, for final approval of the recommendations.